Greetings! Today we will consider all the steering gear protections on the vessel, and also figure out how to check them. For example, the FLUTEK - KAWASAKI steering gear will be considered.
As it happens in ports, port state control comes to the vessel and checks the safety systems of the mechanisms. Very often, the protections and operation of the steering gear are checked according to the register requirements.
What is checked on the steering gear?
- steering gear protections;
- rudder shifting (time and coordination with the bridge);
- emergency control (from the main and emergency power sources);
- emergency communication of the steering gear room (STG room) compartment and the bridge;
- course and rudder repeater in the STG compartment.
In this article, we will mainly discuss issues related to the protections of the steering gear, since this most affects the ETO and it is he who is able to quickly demonstrate the safety system of this mechanism.
First of all, you need to determine what protections exist on the vessel and for this it is enough to look at the steering engine operation monitor, which is usually located on the bridge and in the central control room of the engine room.
In addition, you should pay attention to the alarms that are programmed into the main computer alarm monitoring system in ECR.
The main protections of the steering gear on the vessel:
- Motor over current – overload of the main electric motor;
- Power fail – loss of power supply to the power circuit;
- Phases fail – breakage of phase(s) of the electric motor power circuit;
- Oil level low – low level of hydraulic oil in the expansion tank;
- Auto pilot power fail – loss of power supply to the autopilot;
- Control power fail – loss of power supply to the control circuit;
- Grease pump fail – error of the steering lubrication pump.
Usually, inspectors are not interested in additional protections. It is enough for them to demonstrate the first four, but here it already depends on the wishes of the inspector.
It happens that it is enough to simulate a low oil level and this is the end of the check.
To understand all the protections, let's move on to the electrical circuit of the steering machine.
The diagrams show which relay and contact are responsible for a certain alarm:
- Motor over current - 51Х1;
- Power fail - 27Х;
- Phases fail - 47Х;
- Oil level low - 26Х and timer 1Т3 (10 sec).
In this case, you can simply close the corresponding relay one by one and simulate the alarm we need (the contacts of these relays will open according to the diagram).
But you can't always find such relays in the panels, and very often you come across closed relays. In addition, the inspector may be standing nearby and he will not like such a check. Therefore, there is always an additional method, more correct from the point of view of checking the entire protection circuit.
The float for low level in the tank can be checked using a special test rod. But if it is not there, then you will have to actually reduce the oil in the tank (if the inspector requires it). You can also close/open the contacts inside the float on the contact group, or pull the time relay out of the socket (depending on the circuit). But this is provided that the inspector is not nearby, because all non-standard ways to activate the alarm can lead to a remark (Deficiency).
It is necessary to remember that the delay time of the low level protection response is 10 seconds (timer setting 1T3). In addition, there may also be a delay in the main computer AMS and this time will overlap each other so that the alarm is triggered directly throughout the entire engine room.
Motor overload protection can be checked using a thermal relay, which is located on the main contactor (starter) of the electric motor.
To do this, press the Test button or pull out the flag (it varies) on the thermal one. After checking, you should reset the protection - press the Reset button or push the flag back.
We check the loss of power supply to the power circuit by simply de-energizing the control panel using the circuit breaker on the panel (see the picture "Starter steering panel").
The loss of phase(s) can be checked using a special phase control relay, which must have a Test/Reset button.
You can also try to disconnect one phase of the power circuit in a de-energized state and supply power to the control circuit, but usually it does not come to this.
The loss of power to the control circuit can be checked by removing fuse F13 or F14 of the control circuit.
Loss of power to the autopilot can be checked by de-energizing the autopilot. The panel with the circuit breaker is usually located next to the steering gear starter panel.
Such a check is correct from a safety point of view and gives a complete picture of the operation of all steering gear protections. In the article, I did not mention that the steering gear on each vessel has at least two electric drives (main and auxiliary), sometimes more. Therefore, the check of protections must be duplicated.
We also did not consider the final protections for the rudder shift (for example, 37º) and the hydraulic lock protection system. In my practice, checking these protections occurred very rarely and, as a rule, the intervention of an electrician was not required.
The ship's electrical engineer should prepare several methods of checking the steering gear in advance, so that he can quickly demonstrate all the protections to the inspector. Usually the inspector stands on the bridge and looks at the steering gear monitor, and says which of these protections he wants to check.
When the check is carried out directly on the steering gear (shifting and coordination with the bridge), the inspector is in the STG compartment.
Inspectors like to check the emergency steering control, i.e. on the solenoids. With rare exceptions, they may ask to start the emergency diesel generator, put it on the buses and start the emergency steering gear. If you are asked to check the emergency control, then you must act according to the procedure specified in such cases. Usually, you need to turn off the autopilot and press the buttons on the solenoids using special pins. But everything depends on the model of the steering gear, for example, some machines may have special STBD and PORT switches.
The time of the rudder shift on the vessel is regulated by international and national standards to ensure the maneuverability of the vessel and the safety of navigation. Main parameters of rudder shift time:
Main steering gear:
- Maximum time of rudder shift from one side to the other (from 35° to one side to 35° (37°) to the other side): No more than 28 seconds when the vessel is running (working speed forward).
Emergency steering gear:
- Maximum time of rudder shift from one side to the other (from 15° to one side to 15° to the other side): No more than 60 seconds.
These parameters are established by the requirements of the International Convention for the Safety of Life at Sea (SOLAS) and are taken into account during the design and operation of the vessel.
It is also worth noting that the rudder shift time may depend on the type of vessel, its size and the features of the steering system.
Video of checking the steering gear shifting
Video of a quick check of the main protections of the SFC-80 Mitsubishi steering
The check of the steering gear, which is described above, was done on the FE21-090/77 FLUTEK - KAWASAKI model. And this steering machine does not provide for the Hydraulic lock Alarm protection and signaling system. But on some steering gears such protection is found and below we will consider how to check it. By the way, I have not seen such protection on SFC-80 Mitsubishi steering gears either.
Hydraulic lock Alarm
The steering models in which this protection is provided and with which I worked are RV22-086-H KAWASAKI and PORSGRUNN MacGregor. Let's consider how to test this protection using the MacGregor steering as an example.
Hydraulic lock - protection of the hydraulic system (hydraulic lock) of the steering machine. Unfortunately, there are no photos left, so I will explain only in words. Checking this protection comes down to closing the necessary valves and trying to make a rudder shift. In this case, the system should bypass the hydraulic pressure on the pump (stop the pump) and start the standby pump, if there is a standby (the accompanying alarm should also come out).
Hydraulic lock checking procedure:
- The autopilot system should be in NFU mode.
- Close the bypass valve and activate the pilot valve.
- Make a rudder shift to the right or left. In this case, within 5 - 10 seconds, the working pump should stop and the standby pump should start. The Hydraulic lock Alarm will come out on the bridge and in the ECR.
- Repeat this procedure on the other working pump.
What types of steering gear protections are on a vessel?
Steering gear protection on a ship includes several layers and mechanisms to ensure safe and reliable operation. The main types of steering gear protection include:
1. Mechanical protection:
- Limit switches: Limit the movement of the steering gear, preventing it from going beyond the set limits.
- Overload relay: Protects the steering gear motor from overloads and possible overheating.
- Thermal protection: Includes thermal sensors that turn off the motor when the permissible temperature is exceeded.
2. Electrical protection:
- Circuit breakers and fuses: Prevent damage to electrical circuits in the event of a short circuit or overload.
- Emergency Stop Systems: Allow you to quickly turn off the steering gear in an emergency.
3. Hydraulic protection (if the steering gear is hydraulic):
- Relief valves: Protect the hydraulic system from excess pressure.
- Filters: Prevent contaminants from entering the hydraulic system, which can cause wear and tear and failure of components.
4. Electronic Protection Systems:
- Automatic Control and Diagnostic Systems: Continuously monitors the condition of the steering gear and warns of possible malfunctions.
- Remote Control and Backup Systems: Provides the ability to control the steering gear from different control stations and activate backup systems in the event of failure of the main one.
5. Physical Protection:
- Hull and guards: Protect the steering gear from external influences and prevent unauthorized access.
6. Automatic Shut-off Systems:
Auto-return to Zero Systems: In the event of a failure, the system automatically returns the steering gear to the neutral position.
These protection measures are aimed at ensuring safe operation of the steering gear and preventing emergency situations that could lead to loss of control of the vessel.
By the way, please note that when checking any equipment on a vessel, it is necessary to use manuals and electrical diagrams. If you need instructions on the steering equipment that was discussed in this article, I recommend our closed channel "Marine Engineering Manuals".
I hope this article was useful for you. If you have any questions, write in the comments to the article, I will gladly take part in the discussion.
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